WASHINGTON – Star tennis player Caroline Wozniacki is under fire after stuffing towels in her bra and the rear-end of her shorts to do an impersonation of fellow tennis star Serena Williams.

Critics have assailed the act as racist, saying such an impersonation was not “harmless fun,” reports the Daily Mail.

Wozniacki, 22, was on the court for an exhibition game against Maria Sharapova in Brazil when she made the joke. In a press conference after, she was reported as saying, “I really love the crowd here, they’re open and they have a lot of fun.”

The Daily Mail quotes an article on Feministing.com about the incident: “Given the history and current-day context of racialized standards of beauty, and the hypersexualization of people of color, when a white woman makes fun of a black women’s body, especially in a way that hypersexualizes her and draws on the stereotype of black women’s big butts, it’s racist,”

Serena Williams has been known to make comments about her figure. In July, the Daily Mail reports she tweeted a photo of her rear-end and asked, “Hummm. I think this onzie makes me butt look TOO big. Ugh. #BigButtproblems.”